Electric switch



at, A

m- 17, 1957 A. G. LAUTZENHISER 2,806,918

ELECTRIC SWITCH Filed Nov. 18, 1954 United States Patent ELECTRIC SWITCH Argyle- G;lyautzenhisefiAnderson, Indi, assignor to General Motors=Corporation;i Detroit, Mich., a corporation of-Delaware Application Novemberls, 1954, Serial No. 469,777

4 Glaims.- (Cl; 200-113) This invention relates'to switches and more specifical- 1yto'athertnoresponsivedevice for controlling the flow ofcurrenfin a circuit.

Iti's an object" of the'presentinvention to provide a switchfwh ich will intermittentlybpen and close a circuit lamp suclra's the" turn" signal lamps of a vehicle whi switchha's'a thermoresponsivemember which control's" theope'rationl of'a snap acting contact controlling member'in response to the fiow'of current through the thermoresponsive member;

A further objectfof the present invention is to provide a 'sw'itch with a snap acting contact carrying member that is connectedwith al'wire-like member that is extensible in respcnseto' the flow of curr'entpassing therethrough; \vlier'e'in"tlie"-snap" ac'tingf memb'er is formed of a single piece of metal with integral parts comprising a center portion of rectilinear shape which has extending flange poniens'fornaed on. the periphery'the'reof and an emb'bs'sedor"stressedp'ortionformed by stretching the metal inthe' central part of the re'ctilinear center portion.

Anothe'robject of the-present'invention is to provide a" switch with a snap acting contact carrying member whichis"formed" of"metal to have integral parts which comprise" a rectilinear center portion that'is surrounded by" extending flange portions anda'stressed or embossed portiorffbi med'by stretching the metal in the center of the rectilinear p'brtionl This snap acting member is mounted in the switch so it straddles a bifurcated end of a support and has one of. the flanges urged against an abutment formed on the support when the flange on the opposite side of the rectilinear center portion of said snap member is urged. by the tension applied by a thermoresponsive wire. This wirewhich passes between the arms o'f the'bifurcated. support is adjusted tobe under tension-by. a; capstan screw when the wire is cold so that a moveable contactcarried by the embossed portion will bein engagement withthe stationary contact carried hy the supportathe thermoresponsive wire, when heated bycurrentpassing-therethrough,-elongates to release the tensi'orron the flange to which-it'isconnected and causes the stressed center portion of the contact member to snap over center and cause the engagement with the stationary contact and the circuit through said wire to be broken.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Figure 1 is a top plan view of a switch according to the present invention.

Figure 2 is a bottom plan view of the switch shown in Figure 1.

Figure 3 is an end view taken in the direction of arrow 3 in Figure 2.

Figure 4' is a view, partly-in section, along the line 44 in Figure 1.

In the drawings the numeral 20 designates a switch which is formed with a base 22 of suitable insulating material such as a suitable'plasticas a phenyl formaldehyde condensation product or other suitable material, having an abutment structure 26 with a bifurcated end as defined by arms 24. The abutment structure 26 normally maintains a'pair of terminals 28' and 30 in spaced relation. Terminal 30 is electrically connected through a bent contact arm 32 with a stationary contact 34. Terminal 28 is electrically connected with a moveable contact 36 which is operatively carried by a snap acting contact moving member 38, as will' be hereinafter described, and with a thermoresponsive wire-like element 40 which is wound about a capstan screw 42 which may be locked in position when a nut44 is tightened against terminal 28. The shank portion of the capstan screw 42 extends through the insulating material which forms the body of the abutment portion 26 to maintain the terminals 28 and 30 in position as clearly shown in the drawing. The terminal 30 is insulated from the shank and head portions of screw 42by an insulating grommet 46.

The thermoresponsive member or wire 40, that preferably comprises a wire having a relatively high temperature coeflicient of expansion, which, when cold, is placed under a predetermined tension by an adjustment of thecapstan screw 42. The tension of the wire 40 is transmitted to the snap actingmember 38 to which the wire is connected so as to cause a contact 36 to engage a contact'34l' The snap acting contact actuator 38. is formed of a unitary piece of metal witha rectilinearly shaped center portion 47which is surrounded by peripheral flanges 48, 50, 52 and- 54 as most clearly seen in Figure 1. The flanges 48-'54' are angularly disposed to the center portion 47 and are oriented on one side so that flanges 48 and Stl'will' engage the arms 24 of the support 22. Flanges 52 and 54 are preferably formed at an angle other than a right angle relative to the center portion 47. Flange 54' is fixed relative to the support 22 when an end portion 56 is received in the suitably located slot in the abutment structure 26, see Figure 4. The flange 52 which may be termed'the free end of the snap acting contact member 38 has a roundedend portion 58 to which the wire 40 is suitably secured as by soldering. An em bossed portion 60 is formed in the center of the rectilinearly portion 47 by stretching the metal of the rectilinear center portion 47 towar'dthe flanges 4854.

When the wire element 40 is cold, and under suitable tension, the embossed portion 60,- whereon contact 36 is centrally located, will cause the contact 36 to be moved to the right, as'in Figure 4 so that it will engage the stationary contact'34 to permit the passage of a current between the closed contacts and through the member 38 to the wire 40. The current passing through the wire 40 causes the temperature thereof to rise which in turn causes the wire to elongate and relieve the tension applied on the snap member 38. The reduction in tension on the snap member 38 causes the distance between flanges 512 and 54 to increase; so that flange 52 moves relative to flange 54. The relative movement between flanges 52 and 54 will cause the stress on the center embossed portion 60 to be relieved permitting the center portion 60 to move over the center of a plane as defined by the rectilinear center portion 47 with the snap action which is accompanied by an audible clicking sound. The movement of the center portion 60 causes a separation of contacts 34 and 36. The separation of the contacts causes the passage of electric current through wire 40 to cease and the wire 40 to cool and contract. The contraction of wire 40 causes a tension to be reapplied on member 38, which decreases the distance between flanges 52 and 54 and reestablishes the stress on the embossed center portion 60 so that it again snaps over center to close contacts 34 and 36. The above cycle of opening and closing of the contacts is accompanied by a time delay which can be increased or decreased by varying the tension applied on wire 40 as accomplished by the adjustment of the capstan screw 42.

From the above it is apparent that the switch accord ing to the present invention is adapted to alternately make and break an electric circuit. Switches of this type are particularly suitable for use in flashing signal systems in automotive vehicles and in the installations of this type, the audible clicking sound of the switch as it operates is very desirable for, if the switch is properly located in the vehicle, it will advise the operator of the proper operation of the signalling system. The switch by having a single unitary contact carrying member 38, which is somewhat of a box shape, is highly durable and because of the simplicity thereof will present little prob lems in service.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. In an electric signal actuating device, comprising a thermoresponsive current conducting means which contracts and expands with intermittent flow of current therethrough, a current conducting snap acting switch member formed of a single piece of metal and operatively connected with said thermoresponsive member and having a rectilinear portion, extending flange portions formed along the peripheral edges at an angle on one side of said rectilinear portion and a circulinearly shaped stressed portion centrally formed in said rectilinear center portion, said stressed portion being adapted to carry and move a moveable contact with a snap acting motion in response to a stress which said stress is intermittently applied by said thermoresponsive member.

2. Electric switch means comprising; a support, having a bifurcated end, a snap acting contact actuator straddling the bifurcated end of said support consisting of a single piece of metal and having; a rectilinear center portion with extending flange-like portions formed along the peripheral edges disposed at an angle on one surface side of said rectilinear portion, an embossed portion centrally formed in the center of said rectilinear portion by stretching the metal of said rectilinear portion toward said one surface side of the rectilinear portion, a moveable contact centrally carried on said embossed portion, a stationary contact carried by said support normally out of engagement with said moveable contact and a thermoresponsive means operatively connected with one of said flange-like portions for alternately moving said portion toward the flange-like portion disposed on the opposite edge of said rectilinear portion for causing the contact carried by said stressed portion to be moved with a snap action into and out of engagement with said stationary contact.

3. In an electric signal actuating device, comprising a thermoresponsive current conducting means which expands and contracts with intermittent current flow therethrough, a current conducting metallic tensioned switch member operatively connected with said thermoresponsive member and having a fixed end, a free end and a stressed center portion, an electrical stationary contact arranged adjacent said center portion such that upon alternate flow of current through said thermoresponsive member portions of said tensioned member will be caused to reciprocate and cause a contact as carried on the center portion thereof to alternately touch said stationary contact and alternately close and open an electrical circuit through said thremoresponsive member, said tensioned member being formed from a single piece of metal and having a rectilinearly shaped center portion wherein said stressed center portion is centrally located which stressed center portion is formed by stretching the metal of said member toward one side of said rectilinear center portion and flange portions formed along the peripheral edges of said rectilinear center portion on said free and fixed ends and extending at an angle from the side of said rectilinear center portion toward which the material thereof is stressed, said thermoresponsive member being connected under tension with the flange portion on the free end of said tensioned member whereby the expansion and contraction of said thermoresponsive member will cause a corresponding change in the distance between the fianges of said member for causing a snap action of said stressed center portion.

4. In a device of the character described, a snap acting contact actuator consisting of a member formed of a single piece of metal having a rectilinearly shaped central portion, an extending flange-like portion extendingfrom each of the peripheral edges of said central portion, a curvilinearly shaped embossed portion centrally located in said central portion, a contact secured to said embossed portion, and thermally responsive means arranged to alternately flex one of said flanges toward the flange on the opposite edge of the central portion for causing said embossed portion to move said contact with a snap action.

References Cited in the file of this patent UNITED STATES PATENTS 1,102,566 Besley July 7, 1914 2,041,775 Mottlau May 26, 1936 2,204,792 Davis June 18, 1940 2,299,562 Burch Oct. 20, 1942 2,374,967 Alexander May 1, 1945 2,415,473 Dougherty Feb. 11, 1947 2,571,170 Stilwell Oct. 16, 1951 2,651,748 Talmadge et al Sept. 8, 1953 2,667,552 Walz Jan. 26, 1954' 2,756,304 Welsh July 24, 1956 

